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Background and Aims: Endoscopic ultrasound-guided peripancreatic fluid drainage (EUS-PFD) with on-demand endoscopic necrosectomy, increasingly utilized to manage walled-off necrosis (WON), is associated with substantial morbidity and mortality. This multicenter study aimed to externally validate recently developed quadrant (an abdominal quadrant distribution), necrosis, and infection (QNI) criteria for risk stratification in this setting., Methods: Of 423 patients with pancreatic fluid collections treated in a large multi-institutional cohort between 2010 and 2020, 212 with available preprocedural computed tomography images were included. Clinical outcomes between high- and low-risk groups defined according to QNI criteria were compared., Results: The clinical success rate did not differ significantly between the QNI-high and QNI-low groups (74.4% vs. 83.5%, respectively; P = 0.12). Time to clinical success was longer in the QNI-high group compared with the QNI-low group (median, 68 vs. 46 days, respectively; P = 0.0016). Compared with the QNI-low group, the QNI-high group was associated with higher rates of percutaneous interventions, direct endoscopic necrosectomy, mortality, and adverse events. The QNI-high group was independently associated with time to clinical success (hazard ratio 0.64, 95% confidence interval 0.46-0.87; P =0.005) in multivariable Cox proportional hazards regression analysis, and with the risk of ≥grade III adverse events (odds ratio 2.93, 95% confidence interval 1.04-8.20; P = 0.04) in multivariable logistic regression analysis., Conclusions: The QNI criteria effectively stratified time to clinical success and the risk of adverse outcomes for patients receiving EUS-PFD of WON. Further investigations could elucidate appropriate management strategies based on QNI-based risk stratification., (Copyright © 2025 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: EUS-guided transmural drainage with on-demand endoscopic necrosectomy (EN) is increasingly used to manage walled-off necrosis (WON). It has not been fully elucidated how EN and its timing are correlated with treatment outcomes compared with the drainage-based approach., Methods: Within a multi-institutional cohort of 423 patients with pancreatic fluid collections, including 227 patients with WON, 153 patients were identified who received the step-up treatment after the initial EUS-guided drainage of symptomatic WON; this included 102 EN patients and 51 non-EN (drainage) patients. Using the competing-risks multivariable proportional hazards regression model with adjustment for potential confounders, we calculated subdistribution hazard ratios (SHRs) for clinical treatment success (WON resolution) according to use of EN and its timing., Results: Compared with drainage alone, the EN-based treatment was associated with a shorter time to clinical success with a multivariable SHR of 1.66 (95% confidence interval, 1.12-2.46). Despite a higher risk of procedure-related bleeding in the EN group, there were no differences in the rates of severe adverse events (7.8% vs 5.9% in the EN and non-EN groups, respectively) or mortality (6.9% vs 9.8%). In the EN-treated patients, the timing of EN was not statistically significantly associated with the time to clinical success (P trend  = .34)., Conclusions: Among patients receiving EUS-guided treatment of symptomatic WON, the use of EN in addition to drainage procedures was associated with earlier disease resolution. Further research is desired to determine the optimal timing of initiating EN considering a risk-benefit balance and cost-effectiveness., Competing Interests: Disclosure The following authors disclosed financial relationships: Dr Isayama received support from Boston Scientific Japan, FUJIFILM Corporation, Piolax Medical Devices, Century Medical, Gadelius Medical, FUJIFULM Healthcare, Japan Lifeline Co.,Ltd and ZEON MEDICAL INC. Paid speaker for Boston Scientific Japan, FUJIFILM Corporation, Piolax Medical Devices, Century Medical, CREATE MEDIC, Gadelius Medical, FUJIFULM Healthcare, Japan Lifeline Co., KANEKA MEDIX CORP, Kawasumi Laboratories, Olympus Medical, Sumitomo Bakelite Co., Ltd. and ZEON MEDICAL INC. Consulting for Kawasumi Laboratories. Y. Nakai: research funding and consulting for Boston Scientific Japan, Fujifilm, Gadelius Medical, Hitachi Medical, and Medico’s Hirata; research funding from Century Medical, HOYA Pentax Medical, and Kaneka; and consulting for Olympus Medical and J-MIT. All other authors disclosed no financial relationships. This work was supported by grants from the Japanese Foundation for Research and Promotion of Endoscopy (to Drs. Saito and Nakai). Dr Hamada was supported by the Japan Society for the Promotion of Science KAKENHI grants (JP19K08362 and JP22H02841) and grants from Takeda Science Foundation and Daiichi Sankyo Company. The funders had no role in the study design, data collection and analysis, decision to publish, or manuscript preparation., (Copyright © 2024 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: EUS-guided hepaticogastrostomy (EUS-HGS) carries a risk of serious adverse events (AEs). A newly designed, partially covered laser-cut stent with antimigration anchoring hooks and a thin tapered tip (7.2F), called a Hook stent (Zeon Medical, Tokyo, Japan), has been developed to prevent serious AEs associated with EUS-HGS. The present prospective multicenter clinical trial evaluated the efficacy and safety of the Hook stent for EUS-HGS after failure of ERCP in patients with unresectable malignant biliary obstruction., Methods: The primary endpoint was the rate of clinical success, and secondary endpoints were the rates of technical success, AEs, recurrent biliary obstruction (RBO), procedure success without using a tract dilation device, reintervention for RBO, time to RBO, and overall survival (OS)., Results: Thirty-eight patients underwent EUS-HGS using the Hook stent. The technical and clinical success rates in patients undergoing EUS-HGS were 100% and 92.1%, respectively. The procedure success rate without using a tract dilation device was 94.7%. Four patients (10.5%) developed early AEs, but there were no severe AEs such as stent migration. RBO developed in 26.3% of patients. Reintervention for RBO had a 100% success rate. The median time to RBO was not reached, and the median OS was 191 days., Conclusions: EUS-HGS using the Hook stent demonstrated a high clinical success rate, low rate of early AEs, and an acceptable stent patency. The Hook stent is safe and feasible for use in patients undergoing EUS-HGS. (Clinical trial registration number: jRCT2052210020.)., Competing Interests: Disclosure The following authors disclosed financial relationships: H. Isayama: Speaker for and research support from Fujifilm Corporation. M. Kitano: Speaker for Olympus Corporation; research support from Boston Scientific Corporation and Medicos Hirata Corporation. All other authors disclosed no financial relationships. Masayuki Kitano (the principal investigator), Takeshi Ogura, Hiroyuki Isayama, Mamoru Takenaka, Susumu Hijioka, and Hirotoshi Ishiwatari (the co-investigators) received the research support from the Japan Agency for Medical Research and Development and Zeon Corporation., (Copyright © 2024 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: EUS-guided interventions currently serve as first-line treatment for symptomatic pancreatic fluid collections (PFCs) but require high-level expertise and multidisciplinary care. Hospital caseload has not been fully examined in relation to clinical outcomes of patients with endoscopically managed PFCs., Methods: Using the Diagnosis Procedure Combination database (a Japanese nationwide inpatient database), we identified 4053 patients receiving EUS-guided treatment of PFCs at 486 hospitals between 2010 and 2020 and examined an association of hospital volume (average annual number of cases at a hospital) with in-hospital mortality. Associations with bleeding, length of stay, and total costs were examined as secondary analyses. Multivariable logistic regression analysis was conducted with adjustment for potential confounders., Results: The hospital volume was inversely associated with the risk of in-hospital mortality (P trend  < .001). The adjusted odds ratio for in-hospital mortality comparing the extreme quintiles of hospital volume was .17 (95% confidence interval, .09-.33). A restricted cubic spline analysis yielded no statistically significant evidence on the nonlinear relationship (P nonlinearity  = .19). The types of stents (plastic vs lumen-apposing metal stent) seemed to have no effect modification on the volume-mortality relationship (P interaction  = .58). Higher hospital volume was also associated with lower risk of bleeding, shorter length of stay, and lower medical costs of inpatient care., Conclusions: Higher hospital volume was associated with a lower risk of in-hospital mortality of patients receiving EUS-guided treatment of PFCs. A further investigation is warranted to justify the volume-based selective referral of the patients., (Copyright © 2023 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: We previously reported safety and effectiveness of EUS-guided hepaticogastrostomy (EUS-HGS) using a long, partially covered metal stent (LP-CMS) for malignant biliary obstruction (MBO). In this study, we aimed to evaluate long-term outcomes of EUS-HGS in an expanded cohort., Methods: One hundred ten patients undergoing EUS-HGS using an LP-CMS in 2 centers were retrospectively studied. Technical and functional success, adverse events, recurrent biliary obstruction (RBO), and reinterventions were evaluated., Results: The cause of MBO was pancreatic cancer in 50%, and the location of MBO was distal in 68%. The stent length was 8 cm in 2%, 10 cm in 84%, and 12 cm in 15%, with a median intragastric stent length of 54 mm. Technical and functional success rates were 100% and 94%, respectively. The adverse event rate was 25% (mild 15%, moderate 7%, severe 3%), but about one-half of adverse events were mild transient fever and abdominal pain. RBO developed in 33%, with a median cumulative time to RBO of 6.3 months. The major cause of RBO was hyperplasia at an uncovered portion. The presence of prior biliary drainage and short intragastric stent length were significantly associated with RBO. Reintervention for RBO was successfully achieved through the EUS-HGS route in 92%. The remaining reintervention procedures were 1 EUS-HGS and 2 percutaneous transhepatic biliary drainage all in cases with hilar MBO., Conclusions: EUS-HGS using an LP-CMS for unresectable MBO was safe and effective. RBO was not uncommon, but reintervention through the EUS-HGS route was technically possible in most cases., (Copyright © 2020 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Preoperative biliary drainage with self-expanding metal stents (SEMSs) brings liver function within an acceptable range in preparation for neoadjuvant therapy (NATx) and provides relief of obstructive symptoms in patients with pancreatic cancer. We compared fully-covered SEMSs (FCSEMSs) and uncovered SEMSs (UCSEMSs) for sustained biliary drainage before and during NATx., Methods: Patients with pancreatic cancer and planned NATx who need treatment of jaundice and/or cholestasis before pancreaticoduodenectomy were randomized to FCSEMSs versus UCSEMSs. The primary endpoint was sustained biliary drainage, defined as the absence of reinterventions for biliary obstructive symptoms, and was assessed from SEMS placement until curative intent surgery or at 1 year., Results: The intention-to-treat population included 119 patients (59 FCSEMSs, 60 UCSEMSs). Sustained biliary drainage was equally successful with FCSEMSs and UCSEMSs (72.2% vs 72.9%, noninferiority P = .01). Reasons for FCSEMS and UCSEMS failure differed significantly between the groups and included tumor ingrowth in 0% versus 16.7% (P < .01), and stent migration in 6.8% versus 0% (P = .03), respectively. Serious adverse event rates related to stent placement were not significantly different in both groups (23.7% [14/59] vs 20.0% [12/60], P = .66), as were acute cholecystitis rates when the gallbladder was in situ (9.3% [4/43] vs 4.8% [2/42], P = .68) for FCSEMSs and UCSEMSs, respectively. In our study, independent of stent type, predictors of reinterventions were 4-cm stent length and presence of the gallbladder., Conclusion: FCSEMSs and UCSEMSs provide similar preoperative management of biliary obstruction in patients with pancreatic cancer receiving NATx, but mechanisms of stent dysfunction depend on stent type, stent length, and presence of the gallbladder. (Clinical trial registration number: NCT02238847.)., (Copyright © 2019 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: EUS-guided choledochoduodenostomy (EUS-CDS) using conventional tubular stents has been successfully performed. However, EUS-CDS carries a high risk of bile leakage with attendant adverse events. This study aimed to prospectively evaluate the long-term outcome of EUS-CDS using a dedicated lumen-apposing metal stent (LAMS)., Methods: Nineteen patients (mean age, 70.6 years; 12 men) with unresectable malignant diseases were treated in 5 tertiary referral centers. EUS-CDS was performed using a fully covered LAMS with a cautery-enhanced delivery system for EUS-CDS., Results: All stents were successfully deployed without any adverse events. Jaundice improved in 79% of the patients within 7 days and finally in 95%. In 95% of patients the stents remained in good anastomotic position without migration or dislocation during the follow-up period (median, 184 days; range, 12-819). One patient had a fever the day after stent placement. During the follow-up period 5 patients had secondary stent obstruction because of food residue (n = 2), kinking (n = 1), suspected tumor ingrowth (n = 1), and spontaneous dislodgement (n = 1). Five patients developed obstruction in the second portion of the duodenum. The overall adverse event rate was 36.8% (7/19), mostly with mild severity., Conclusions: This study revealed that the novel dedicated LAMS used has high technical and clinical success rates for EUS-CDS. The adverse events and patency rates are inferior to the historically reported data of a conventional transpapillary metal stent. Development of a more suitable dedicated LAMS is anticipated., (Copyright © 2018 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: A side-port needle has been developed to improve diagnostic accuracy by obtaining more cellular material during EUS-guided FNA (EUS-FNA). We compared the accuracy rate of histology and the quality of histologic specimens from 22-gauge (G) side-port and standard needles for EUS-FNA of a solid pancreatic mass in a multicenter, prospective, randomized control trial., Methods: Between January 2013 and September 2013, 160 consecutive patients with a suspected solid pancreatic mass at 5 tertiary referral centers were enrolled. Patients were randomized to the 22G side-port needle or 22G standard needle group. The primary endpoint was the diagnostic accuracy of histology. Secondary endpoints were the quality of the histologic specimen (quantity of tissue, degree of GI contamination, and amount of blood)., Results: An analysis of 154 patients (side-port, 76, vs standard, 78) was performed. Six patients were excluded because of no pancreatic mass on EUS. There was no significant difference in the rate of diagnostic accuracy of histology (side-port, 87% [66/76], vs standard, 82% [64/78]; P = .51). Samples that enabled histologic interpretation were obtained in 64% (47/73) and 43% (33/77) of patients from the side-port and standard groups, respectively (P = .009). No significant difference was seen in the degree of GI contamination and amount of blood between groups., Conclusions: There was no significant difference in the accuracy rate of histology between needle types. The side-port needle was superior to the standard needle in terms of obtaining samples that enabled histologic interpretation., (Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aims: In EUS-guided FNA (EUS-FNA), small-caliber needles are preferable for optimal cytologic yield, whereas large ones are preferable when histologic specimens are needed. Because of the rigidity and friction induced by its large caliber, however, technical limitation does exist in a 19-gauge FNA needle. Recent development of miniature biopsy forceps enables EUS-guided through-the-needle forceps biopsy (EUS-TTNFB). The aim of this study is to evaluate safety and efficacy of EUS-TTNFB., Methods: Eighteen sessions of EUS-TTNFB in 17 patients with solid lesions were performed by using a 0.75-mm biopsy forceps through a 19-gauge FNA needle. Technical feasibility, safety, and diagnostic yield of EUS-TTNFB were retrospectively studied., Results: A total of 49 passes, a median of 3 passes per session, were performed, and the needle puncture, advancement and removal of the biopsy forceps, and subsequent EUS-FNA were technically successful in all patients. No adverse events were observed other than one case with hyperamylasemia without pancreatitis. Macroscopic histologic core by EUS-TTNFB was obtained at a rate of 71% per pass. The tissue acquisition rate by EUS-TTNFB alone was 67% per pass and 100% per session. When EUS-TTNFB and subsequent EUS-FNA were combined, the tissue acquisition rate was 94% per pass. The accuracy of combined EUS-TTNFB and EUS-FNA to diagnose malignancy was 88% per pass and 94% per session. With a single pass of EUS-TTNFB and EUS-FNA, the tissue acquisition rate was 89%, and the accuracy to diagnose malignancy was 83%., Conclusions: EUS-TTNFB was safe and technically feasible and provided additional tissue acquisition with a single puncture of a 19-gauge FNA needle., (Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: EUS-guided FNA (EUS-FNA) has become the most efficacious way to obtain specimens from a solid lesion adjacent to the GI tract. Previous reports regarding the use of a stylet during EUS-FNA were all based on cytological diagnosis and have showed no significant superiority in terms of diagnostic yield., Objective: To clarify the noninferiority of EUS-FNA without a stylet (S-) compared with EUS-FNA with a stylet (S+) on histological assessment., Design: A prospective, single-blind, randomized, controlled crossover study., Setting: Five tertiary referral centers in Japan., Patients: Patients referred for EUS-FNA of a solid lesion., Intervention: EUS-FNA S+ and S- in a total of 4 alternate passes with randomization to S+ first or S- first., Main Outcome Measurements: The primary endpoint was the acquisition rate of an appropriate and sufficient specimen for histological assessment. The secondary endpoints were cellularity, contamination, bloodiness, diagnostic ability, and diagnostic accuracy., Results: We enrolled 107 patients (110 lesions) and analyzed 220 specimens each in the S+ and S- groups. The acquisition rate of appropriate and sufficient specimens in the S+ group was 121 of 220 (55.0%) and 122 of 220 (55.5%) in the S- group. The difference in the acquisition rate of the specimen (S- minus S+) based on the generalized estimating equation was 0.42% (95% confidence interval, -6.72% to 7.56%), which was less than 10% of the prespecified noninferiority margin of this study. With regard to cellularity, contamination, bloodiness score, diagnostic ability, and diagnostic accuracy, there were no significant differences between both groups. There were no dropouts in the study., Limitations: A variety of target lesions, multiple pathologists, lack of an assessment of intraobserver and interobserver variability, and a single-blind study for the pathologists., Conclusion: EUS-FNA S- is noninferior to EUS-FNA S+ on histological assessment. (, Clinical Trial Registration Number: UMIN000008695.)., (Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: Endoscopic self-expandable metal stent placement has been used as an alternative to surgery for malignant colorectal obstruction; however, factors affecting its clinical outcome are unclear., Objective: To clarify the short-term safety and efficacy of endoscopic self-expandable metal stent placement for malignant colorectal obstruction and to identify factors associated with its clinical and technical failure., Design: Prospective clinical cohort study., Setting: Fourteen academic centers and 32 community hospitals., Patients: A total of 513 consecutive patients with malignant colorectal obstruction., Intervention: Endoscopic self-expandable metal stent placement, sharing of stent placement methods among participating facilities., Main Outcome Measurements: The primary endpoint was clinical success, defined as symptom and radiological finding resolution within 24 hours. Secondary endpoints were technical success and adverse events. The follow-up period was 7 days., Results: The clinical and technical success rates were 95.5% and 97.9%, respectively. Major adverse events included perforation (2.1%), stent migration (1.0%), and stent occlusion (0.8%). The main causes of perforation were the procedure itself (0.8%) and comorbidities (obstructive colitis and impending perforation) not apparent before stent placement (0.6%). Extrinsic tumor origin was independently associated with the clinical failure after stent placement (odds ratio 4.23; 95% confidence interval, 1.21-14.79; P = .02). Stricture marking trended toward a negative association with technical failure (P = .09)., Limitations: Noncomparative study., Conclusion: Strict inclusion criteria and stricture marking may improve the technical and clinical success of stent placement., (Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: Wire-guided cannulation (WGC) was reported to decrease post-ERCP pancreatitis (PEP), but risk factors for PEP in WGC are not fully elucidated., Objective: To evaluate the incidence and risk factors of PEP in WGC., Design: Single-center retrospective study., Setting: Academic center., Patients: A total of 800 consecutive patients with a native papilla., Interventions: Biliary therapeutic ERCP by using WGC., Main Outcome Measurements: The rate of PEP and its risk factors., Results: Biliary cannulation was successful by using WGC alone in 70.5%, and the final cannulation rate was 96.1%. Unintentional guidewire insertion and contrast material injection into the pancreatic duct (PD) during cannulation occurred in 55.3% and 21.8%, respectively. The incidence of PEP was 9.5% (mild 5.6%, moderate 2.9%, severe 1.0%). Multivariate analysis revealed a common bile duct (CBD) diameter of <9 mm (odds ratio [OR] 2.03; P = .006) and unintentional guidewire insertion into the PD (OR 2.25; P = .014) as risk factors for PEP. PD opacification was not a risk factor for PEP (OR 1.15; P = .642), but the incremental increase of the PEP rate was seen in patients with CBDs <9 mm: 4.6% without any PD manipulation, 8.3% with contrast material alone, 16.9% with guidewire alone, and 22.1% with both contrast material and guidewire., Limitations: Retrospective design in a single center., Conclusion: Unintentional PD manipulation was not uncommon in WGC. Guidewire insertion into the PD and a small CBD were risk factors for PEP in biliary therapeutic ERCP with the use of WGC., (Copyright © 2015. Published by Elsevier Inc.)

Background: EUS-guided FNA (EUS-FNA) has a high diagnostic accuracy for pancreatic diseases. However, although most reports have typically focused on cytology, histological tissue quality has rarely been investigated. The effectiveness of EUS-FNA combined with high negative pressure (HNP) suction was recently indicated for tissue acquisition, but has not thus far been tested in a prospective, randomized clinical trial., Objective: To evaluate the adequacy of EUS-FNA with HNP for the histological diagnosis of pancreatic lesions by using 25-gauge needles., Design: Prospective, single-blind, randomized, controlled crossover trial., Setting: Seven tertiary referral centers., Patients: Patients referred for EUS-FNA of pancreatic solid lesions. From July 2011 to April 2012, 90 patients underwent EUS-FNA of pancreatic solid masses by using normal negative pressure (NNP) and HNP with 2 respective passes. The order of the passes was randomized, and the sample adequacy, quality, and histology were evaluated by a single expert pathologist., Intervention: EUS-FNA by using NNP and HNP., Main Outcome Measurements: The adequacy of tissue acquisition and the accuracy of histological diagnoses made by using the EUS-FNA technique with HNP., Results: We found that 72.2% (65/90) and 90% (81/90) of the specimens obtained using NNP and HNP, respectively, were adequate for histological diagnosis (P = .0003, McNemar test). For 73.3% (66/90) and 82.2% (74/90) of the specimens obtained by using NNP and HNP, respectively, an accurate diagnosis was achieved (P = .06, McNemar test). Pancreatitis developed in 1 patient after this procedure, which subsided with conservative therapy., Limitations: This was a single-blinded, crossover study., Conclusion: Biopsy procedures that combine the EUS-FNA with HNP techniques are superior to EUS-FNA with NNP procedures for tissue acquisition. (, Clinical Trial Registration Number: UMIN000005939.)., (Copyright © 2014 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: A lumen-apposing stent can be used effectively under endosonographic guidance., Objective: To evaluate a newly designed, fully covered self-expandable metal stent with folding anchoring flanges for lumen apposition assembled on a conventional delivery system., Design: Retrospective case series and animal study., Setting: Tertiary care academic medical centers., Subjects: Six pigs for animal study and 7 patients, 3 of whom underwent endoscopic drainage for acute cholecystitis (AC) and 4 for pancreatic fluid collection (PFC)., Intervention: Stent deployment under EUS guidance after puncturing, passage of an endoscope through the stent into the gallbladder (GB), or PFC with conventional endoscopic procedures., Main Outcome Measurements: Technical and clinical success, adverse events, and removability., Results: In the animal study, the stent was successfully inserted and deployed in the GB via a transgastric approach under EUS guidance without adverse events in all 6 pigs. Contrast injection demonstrated the absence of leakage. Cholecystoscopy with enhanced endoscopy was performed successfully in all animals after stent placement. All stents were intact and were removed successfully at 4 weeks. GB firmly adhered to the stomach with an intact cholecystogastric tract on necropsy and histopathology. The stents were successfully deployed without adverse effects in 7 patients. AC or PFC was resolved after stent placement in all patients. Endoscopic procedures were possible through the stent. Stent migration was not observed. The stent was successfully removed from the 4 patients with PFC after complete resolution., Limitations: Small sample size, retrospective study., Conclusions: Transenteric drainage and endoscopic intervention by using a novel fully covered self-expandable metal stent for lumen apposition under EUS guidance is feasible for the management of AC and PFC. Further study is warranted., (Copyright © 2014 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Endoscopic removal of pancreatic stones in patients with chronic pancreatitis is still challenging. With a conventional basket catheter, introduction to the target area or catching pancreatic stones is sometimes difficult., Objective: To evaluate a novel double-lumen basket catheter composed of nitinol wires with fine reticular structures in the distal end and loose mesh in the proximal part., Design: A prospective feasibility study., Setting: Tertiary-care center., Patients: This study involved 10 patients with main pancreatic duct stones of 5 mm or less in the shorter diameter of the largest stone., Intervention: In the first 5 cases, a nitinol basket catheter was used as salvage after stone extraction with a conventional basket catheter and retrieval balloon (salvage group). In the following 5 cases, stones were initially removed by using a nitinol basket catheter, and the presence of residual stones was evaluated by pancreatogram along with balloon sweep (initial group)., Main Outcome Measurements: Success rate of removal of the target stones and procedure-related adverse events., Results: A nitinol basket catheter was easily introduced to the target stone in all patients. In the salvage group, additional stones were retrieved with a nitinol basket catheter in 3 of 5 patients. In the initial group, stone extraction by a nitinol basket catheter was successful, and no residual stones were extracted by additional balloon cleaning in any patients. Basket impaction or after-ERCP pancreatitis was not observed., Limitations: A small sample size without a control group., Conclusion: This novel nitinol basket catheter is useful for the extraction of small pancreatic stones. A randomized, controlled trial is warranted to confirm its efficacy., (Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Our previous study suggested that a combination of ulinastatin and risperidone reduced post-ERCP pancreatitis (PEP) compared with ulinastatin alone., Objective: The aim of this study was to evaluate the efficacy of risperidone alone for prevention of PEP., Design: A multicenter, randomized, placebo-controlled, double-blind clinical trial., Setting: Two academic hospitals and 5 referral hospitals in Tokyo and Saitama, Japan., Patients: Patients undergoing therapeutic or interventional-diagnostic ERCP., Intervention: The patients were randomized to receive 2 mg of oral risperidone or oral placebo at 0.5 to 2 hours before ERCP., Main Outcome Measurements: The primary endpoint was the incidence of PEP. Secondary endpoints were the incidence of hyperenzymemia and enzyme levels (amylase, pancreatic amylase, lipase). Risk factors for PEP were evaluated., Results: We initially enrolled 500 patients in the study (250 in the risperidone group and 250 in the placebo group), but 17 (11 in the risperidone and 6 in the placebo group) were excluded after randomization. PEP developed in 24 patients (10.0%) in the risperidone group and 21 patients (8.6%) in the placebo group (P = .587). Serum amylase levels at 3 hours after ERCP were lower in the risperidone group (P = .007 in a single test of hypothesis, significance removed by Bonferroni correction for multiple testing). In multivariate analysis, a small papilla of Vater, total procedure time ≥40 minutes, and stenosis of the intrahepatic duct were significantly associated with PEP., Limitations: Multiplicity of study centers and a relatively wide time range of drug administration time., Conclusion: Risperidone did not show a benefit in prevention of PEP in this trial. (, Clinical Trial Registration Number: NCT000004592.)., (Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: There are few in vivo and ex vivo models for training in endoscopic sphincterotomy (ES) and endoscopic papillectomy (EP)., Objective: We describe in vivo and ex vivo training pig models that use a simulated papilla for hands-on teaching of ES and EP., Design: Animal experiment., Setting: A referral center., Materials and Interventions: Hyaluronate solution (0.4%) was injected submucosally using a 25-gauge sclerotherapy needle to create a submucosal bleb by using porcine in vivo stomach, ex vivo stomach, and ex vivo rectum. ES and EP were then performed by using a pull-type sphincterotome and snare, respectively., Main Outcome Measurement: The feasibility of creating a simulated papilla for ES and EP procedures was tested by experienced and nonexperienced ERCP endoscopists., Results: Creation of a hemispheroidal bulge was successful in 13 of 17 (76%) areas within an in vivo stomach, 13 of 16 (81%) areas of an ex vivo stomach, and 16 of 16 (100%) areas in an ex vivo rectum. In the in vivo stomach model, ES was successfully and realistically performed on the anterior wall of the stomach rather than in other walls. In the ex vivo stomach model, endoscopists experienced in ERCP and trainees performed ES without difficulty, whereas it was difficult or impossible for nonexperienced trainees to perform ES. In the ex vivo rectum model, all 3 endoscopists were able to complete not only ES but also EP., Limitations: Pilot study., Conclusions: Although further studies are necessary to evaluate the reproducibility and cost-effectiveness, this novel pig model appears useful for ES and EP training., (Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Endoscopic transluminal treatment of pancreatic fluid collections (PFC) has been reported as an effective alternative approach to surgical treatment. A wide, short stent with an anti-migration system has been developed., Objective: To evaluate a newly developed, fully covered, self-expandable metal stent (FCSEMS) customized for cystogastrostomy., Design: Retrospective case series., Setting: Tertiary-care academic medical centers and affiliated hospitals., Patients: Nine patients who underwent endoscopic treatment of PFCs (5 with pseudocysts and 4 with walled-off pancreatic necrosis)., Intervention: Stent deployment after endoscopic US-guided puncture. Irrigation and necrosectomy were performed at the discretion of the endoscopist., Main Outcome Measurements: Technical and clinical success rate, complications, and removability., Results: The FCSEMS was inserted successfully in all cases (9/9, 100%). Clinical success was achieved in 7 of 9 cases (77.8%). No early complications associated with the procedure were observed. Late complications were observed in 2 cases (bleeding and asymptomatic migration). The FCSEMS was removed without any complications in all 6 cases where it was attempted after the procedure had been completed (100%)., Limitations: This was a retrospective evaluation of a small number of cases. The FCSEMS was always inserted via the transgastric route. Follow-up duration was short., Conclusion: The endoscopic approach that uses this new FCSEMS is feasible for the treatment of PFCs. However, further evaluation is required., (Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Covered self-expandable metal stents (CSEMSs) were developed to prevent tumor ingrowth, but stent migration is one of the problems with CSEMSs., Objective: To evaluate a new, commercially available CSEMS with flared ends and low axial force compared with a commercially available CSEMS without the anti-migration system and high axial force., Design: Multicenter, prospective study with a historical cohort., Setting: Twenty Japanese referral centers., Patients: This study involved patients with unresectable distal malignant biliary obstruction., Intervention: Placement of a new, commercially available, partially covered SEMS., Main Outcome Measurements: Recurrent biliary obstruction rate, time to recurrent biliary obstruction, stent-related complications, survival., Results: Between April 2009 and March 2010, 141 patients underwent partially covered nitinol stent placement, and between May 2001 and January 2007, 138 patients underwent placement of partially covered stainless stents as a historical control. The silicone cover of the partially covered nitinol stents prevented tumor ingrowth. There were no significant differences in survival (229 vs 219 days; P = .250) or the rate of recurrent biliary obstruction (33% vs 38%; P = .385) between partially covered nitinol stents and partially covered stainless stents. Stent migration was less frequent (8% vs 17%; P = .019), and time to recurrent biliary obstruction was significantly longer (373 vs 285 days; P = .007) with partially covered nitinol stents. Stent removal was successful in 26 of 27 patients (96%)., Limitations: Nonrandomized, controlled trial., Conclusion: Partially covered nitinol stents with an anti-migration system and less axial force demonstrated longer time to recurrent biliary obstruction with no tumor ingrowth and less stent migration., (Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: A high incidence of migration with covered metal stents has been reported in malignant gastric outlet obstruction (GOO). A newly modified, partially covered, triple-layer nitinol stent was developed that has a longer uncovered portion (5-15 mm) to prevent stent migration., Objective: To estimate the efficacy and safety of the modified covered, triple-layer metal stent., Design: Multicenter, prospective cohort study., Setting: Three tertiary referral centers., Patients: Fifty consecutive patients (26 with pancreatic carcinoma, 14 with gastric carcinoma, 9 with cholangiocarcinoma, 1 with a metastatic node) who presented with symptomatic unresectable malignant GOO between April 2007 and March 2010., Interventions: Endoscopic placement of the modified covered, triple-layer metal stent., Main Outcome Measurements: The primary endpoint was to improve the GOO scoring system (GOOSS) score. Secondary endpoints were success rate, patency, and complications., Results: The median GOOSS score improved significantly (P < .0001) after stenting (from 0 to 3). The technical and clinical success rates were 100% and 90%, respectively. Stent occlusion by tumor overgrowth or ingrowth at the uncovered portion developed in 5 patients (10%). Asymptomatic stent migration occurred in 3 patients (6%) receiving chemotherapy at 95, 230, and 553 days after stent placement, but these patients tolerated solid food 68, 260, and 142 days after stent migration, respectively. Other complications occurred in 1 patient with insufficient expansion, cholangitis, and pancreatitis. No procedure-related deaths occurred., Limitations: A single-arm study in tertiary-care centers., Conclusions: The modified covered, triple-layer metal stent was effective and safe for managing malignant GOO and can prevent tumor ingrowth and stent migration. (, Clinical Trial Registration Number: UMIN000004566.)., (Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Wire-guided cannulation (WGC) with a sphincterotome (S) for selective bile duct cannulation (SBDC) has been reported to have a higher success rate and lower incidence of post-ERCP pancreatitis (PEP) than conventional methods in some randomized, controlled trials (RCTs) that were both single center and limited to only a few endoscopists., Objective: To estimate the difference in SBDC according to the method and catheter used in a multicenter and multiendoscopist study., Design: A prospective, multicenter RCT with a 2 × 2 factorial design., Setting: Fifteen referral endoscopy units., Patients: In total, 400 consecutive patients with naive papillae who were candidates for ERCP were enrolled and randomized., Interventions: Patients were assigned to 4 groups according to combined catheter (S or catheter [C]) and method (with/without guidewire [GW])., Main Outcome Measurements: Success rate of SBDC performed in 10 minutes, SBDC time, fluoroscopy time, and incidence of complications., Results: There was no significant difference in the SBDC success rate between the groups with and without GW, between C and S, or among the 4 groups (C+GW, C, S+GW, S). WGC had a tendency to significantly shorten cannulation and fluoroscopy times only in approximately 70% of patients in this study in whom SBDC was achieved in 10 minutes or less (P = .036 and .00004, respectively). All 4 groups resulted in similar outcomes in PEP (4%, 5.9%, 2%, and 2.1%, respectively)., Limitations: Non-double-blind study., Conclusions: WGC appears to significantly shorten cannulation and fluoroscopy times. However, neither the method nor type of catheter used resulted in significant differences in either SBDC success rate or incidence of PEP in this RCT. (, Clinical Trial Registration Number: UMIN000002572.)., (Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Although the placement of self-expandable metal stents (SEMSs) has been widely accepted as palliation for distal malignant biliary obstruction, the risk factors for their early dysfunction remain unclear., Objective: To identify risk factors for early (<3 months) SEMS dysfunction in unresectable pancreatic cancer., Design: A multicenter retrospective study., Setting: Five tertiary referral centers., Patients: Patients were included who underwent first-time SEMS placement for distal malignant biliary obstruction caused by pancreatic cancer between April 1994 and August 2010., Main Outcome Measurements: Rates and causes of early dysfunction were evaluated, and risk factors were analyzed., Results: In all, 317 eligible patients were identified. Covered SEMSs were placed in 82% of patients. Duodenal invasion was observed endoscopically in 37%. The median time to dysfunction was 170 days. The rates of all and early SEMS dysfunction were 55% and 31%, respectively. The major causes of SEMS dysfunction were food impaction and nonocclusion cholangitis (21% each) in early dysfunction and sludge (29%) in nonearly dysfunction. The rate of early dysfunction was 42% with duodenal invasion and 24% without duodenal invasion (P = .001). Early dysfunction caused by food impaction was more frequent in patients with duodenal invasion (10% and 4%, P = .053). Duodenal invasion was a risk factor (odds ratio 2.35; 95% CI, 1.43-3.90; P = .001) in a multiple logistic regression model., Limitations: A retrospective design., Conclusions: Duodenal invasion is a risk factor for early SEMS dysfunction in patients with pancreatic cancer., (Copyright © 2011 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Intrapancreatic bile duct stricture in autoimmune pancreatitis (AIP) is usually diagnosed as sclerosing cholangitis even if the stricture is limited to the intrapancreatic area. However, it is not known whether compression caused by pancreatic edema or biliary wall thickening causes such a biliary stricture., Objective: Our purpose was to clarify the factor that contributes to intrapancreatic biliary stricture in AIP: pancreatic head lesion or biliary wall thickening., Design: Single-center retrospective study., Setting: This study was performed in a tertiary care academic medical center., Patients: Fifty-six patients with AIP were included., Main Outcome Measurements: The relationship between the presence of a pancreatic head lesion and intrapancreatic biliary stricture was examined. In addition, the relationship between the extent of the intrapancreatic biliary stricture and the wall thickening was evaluated., Results: Among 44 patients with a pancreatic head lesion, 41 (93%) had intrapancreatic bile duct stricture. Among 12 patients without a pancreatic head lesion, only 2 had such a stricture (P < .0001). Intraductal US showed average intrapancreatic biliary wall thickening with severe stricture of 2.7 +/- 1.0 mm, significantly thicker than that with mild stricture (1.9 +/- 0.35 mm; P = .0200)., Limitations: Intraductal US was not performed in all patients., Conclusions: Both pancreatic edema and biliary wall thickening influenced intrapancreatic biliary stricture in AIP. This type of stricture should be differentiated from extrapancreatic biliary stricture that may be caused by biliary wall thickening only., (2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Efforts to understand the properties of self-expandable metallic stents (SEMSs) through their mechanical properties have progressed. Among them, radial force (RF) is well known as an expanding force, but axial force (AF) has not been measured before. Correlations of these properties to clinical results are not well known., Objective: We measured RF and AF of 14 different SEMSs and discussed the results in terms of clinical implications., Design: Experimental study., Subjects: Measurement of RF and AF of 14 different covered and uncovered SEMSs., Methods: RF was measured with an RF measurement machine manufactured by Machine Solution, and AF was measured with in-house equipment., Results: Measurements of RF in the process of expansion showed characteristic patterns closely related to the structures and materials of SEMSs. Results of AF measurement can be classified into 3 groups: high, medium, and low AF, depending on the type of SEMS. AF decreased with an increase of the length of stents. A plot of RF against AF revealed 3 distinguished RF/AF combinations and indicated the importance of understanding the properties by not only RF or AF individually but also by RF/AF combination., Limitations: In vitro study using measurement equipment., Conclusion: It was demonstrated that a combination of RF and AF is more effective than RF or AF individually in understanding the clinical implications of SEMSs. More work is needed to correlate mechanical properties with clinical results by designing model experiments.

Background: Endoscopic papillary balloon dilation (EPBD) is a possible alternative to endoscopic sphincterotomy for the treatment of bile duct stones. However, little information is available in the elderly., Objective: Our purpose was to evaluate the safety and efficacy of EPBD for bile duct stones in patients of 85 years of age and older., Design: Retrospective study from a single center., Setting: Tertiary care facility with experience in bile duct stone removal with EPBD., Patients: A total of 406 patients (74 patients >/=85 years old, group A; 332 patients <85 years old, group B) with bile duct stones underwent EPBD., Main Outcome Measurements: Efficacy and safety of EPBD between the 2 groups. Baseline patient characteristics were also evaluated., Results: The mean American Society of Anesthesiologists score in group A was significantly higher compared with that in group B (2.4 [0.5] vs 1.9 [0.7], P < .0001). Patients received anticoagulants more frequently and had larger and more numerous stones in group A than in group B with significant differences. Overall, bile duct clearance rates were similar in the 2 groups (91% vs 95%), but the mean number of sessions required for complete stone removal was significantly higher in group A (1.6 vs 1.4, P = .0081). The incidence of overall early complications after EPBD was lower in group A than in group B (2.7% vs 8.4%) but was not statistically different. None of the patients in group A had post-EPBD pancreatitis, whereas pancreatitis occurred in 5.7% in group B (P = .036). Bleeding was not observed after EPBD in 406 patients, including 7 patients in group A who received anticoagulation therapy at the time of EPBD. There was no significant difference in the cumulative stone nonrecurrence rate between group A and group B (log-rank test, P = .6225)., Conclusions: EPBD is a safe and effective technique for the treatment of bile duct stones even in high-risk elderly patients without an increased risk of pancreatitis and bleeding. Because the evaluation of outcomes might be biased by our study design (an open study), further studies are needed.

Background: Tumor involvement to the orifice of the cystic duct (OCD) is a risk factor for cholecystitis after metallic stent (MS) placement., Objective: ERCP and intraductal US (IDUS) were used to assess tumor involvement to the OCD., Design: A prospective consecutive study., Setting: The University of Tokyo Hospital, Japan., Patients and Interventions: Between January 2003 and May 2007, 34 patients with resectable malignant biliary obstruction underwent an ERCP and an IDUS before preoperative biliary drainage., Main Outcome Measurements: ERCP and IDUS findings were confirmed via a histopathologic analysis of surgical specimens., Results: An ERCP showed that the cystic duct was opacified in 22 of 34 patients (64.7%). Eight patients were diagnosed with OCD tumor involvement. In the remaining 12 patients, tumor involvement was impossible to evaluate via an ERCP. An IDUS identified tumor involvement to the OCD in all 34 patients. Tumor involvement to the OCD was diagnosed in 12 patients, including 4 patients with previously negative results during an ERCP. Tumor involvement was confirmed by histopathology of surgical specimens. The sensitivity and specificity of detection were 66.7% (8/12) and 63.6% (14/22), respectively, via ERCP, and 100% (12/12) and 100% (22/22), respectively, via IDUS., Limitation: The small sample size., Conclusions: IDUS, in addition to ERCP, provides an accurate evaluation of tumor involvement to the OCD in patients with malignant biliary obstruction.

Background: Through-the-scope (TTS) stents facilitate palliative enteral stent placement. However, most TTS stents are braided, a characteristic that has been associated with significant foreshortening and relatively frequent migration., Objectives: To evaluate clinical experience with a new woven enteral stent in the treatment of gastric outlet obstruction., Design: From January 2005 to August 2006, patients with unresectable malignant gastric outlet obstruction were offered stent placement with a new woven stent., Setting: Three referral hospitals in Japan., Patients: Thirty-seven consecutive patients with malignant gastric outlet obstruction., Interventions: A newly designed enteral stent was placed by using the TTS placement technique., Main Outcome Measurements: Palliation efficacy and safety of the new stents., Results: Stent placement was successful in 36 of 37 patients (technical success, 97%). Thirty-four patients were able to tolerate oral intake without obstructive symptoms (clinical success, 94.4%). Complications occurred in 16.2% of patients, comprising 2 cases of primary stent dysfunction, 1 perforation, 1 GI bleeding, 1 stent obstruction, and 1 biliary stent dysfunction. No migration was seen during the median follow-up period of 68 days., Limitations: Small sample size and relatively brief follow-up., Conclusions: A newly developed enteral stent with higher flexibility and less foreshortening offers comparable clinical outcome to existing stents and a lower frequency of complications, including migration.

Background: The aim of this study was to evaluate the efficacy and the safety of the covered Wallstent, a commercially available silicone-covered, self-expandable metallic stent (covered Wallstent), for the treatment of distal malignant biliary obstruction., Methods: Sixty-nine consecutive patients with unresectable distal malignant biliary obstruction who underwent covered Wallstent placement between October 2001 and October 2003 were studied at 4 affiliated hospitals., Results: Mean stent patency and mean survival were 139.1 days and 200.9 days, respectively. Stent occlusion occurred in 7 cases (10.1%), but tumor ingrowth was not observed. Seventeen complications, including 5 cholangitis (7.2%), 4 stent migration (5.8%), 4 cholecystitis (5.8%), and 4 pancreatitis (5.8%) were observed in 16 patients (23.2%). Stent misplacement was observed in 7 patients (10.1%)., Conclusions: Covered Wallstent is effective in preventing tumor ingrowth for the treatment of distal malignant biliary obstruction. However, the overall complication rate may be higher than uncovered self-expanding metal stents and covered self-expanding metal stents of different design.

Background: The efficacy of polyurethane-covered metal expandable stents for treatment of neoplastic distal biliary obstruction was analyzed., Methods: Twenty-one patients with unresectable malignant tumors involving the mid to distal bile duct who were seen with obstructive jaundice were consecutively enrolled. Eighteen patients underwent endoscopic implantation of a polyurethane-covered metal stent and 3 patients underwent transhepatic insertion because of duodenal obstruction. The stent patency, complications, and patient survival were analyzed., Results: Effective biliary decompression was achieved in all patients. Adverse events were minor: mild pancreatitis (1) and cholecystitis (2) occurred within 7 days of stent insertion. Mean survival and stent patency were 233 days and 206 days, respectively. Stent occlusion occurred in 3 patients (14%) after a mean of 188 days. Tumor ingrowth through the stent mesh was not observed. However, 2 stents were occluded by tumor overgrowth and 1 by compacted alimentary debris., Conclusions: A polyurethane membrane may prevent tumor ingrowth and reduce the occlusion rate for expandable metal stents implanted in patients with malignant obstruction of the distal bile duct.

Background: Complete bile duct clearance of stones should be achieved in patients managed with endoscopic papillary balloon dilation. However, complete retrieval of small stones or tiny fragments sometimes proves difficult using conventional devices., Methods: We attempted the removal of fine stone fragments by saline infusion using a specially designed retrieval balloon catheter with a blind tip and a side hole located proximal to the balloon in 14 patients., Results: Using this technique, bile duct clearance was achieved in a single attempt in 13 of 14 patients; 2 attempts were required in 1 patient. Cholecystitis occurred in 2 patients with gallstones in situ after the procedure., Conclusions: Saline washout using a side-holed retrieval balloon catheter effectively cleans stones and stone fragments from the bile duct in patients treated with endoscopic papillary balloon dilation.